IPA: /ˈkaʊntərˌveɪl/
KK: /ˈkaʊntərˌveɪl/
To act against something in order to balance or counteract it, often by providing an opposing force or influence.
The new policy was designed to countervail the negative effects of the previous regulations.
Past: countervailed
Past Participle: countervailed
Countervail → It is formed from "counter-" (meaning against) and "vail" (from Latin "valere", meaning to be strong or to be worth). The word "countervail" means to act against something in order to offset or counterbalance it.
Think of acting 'against' ('counter-') something that is 'strong' ('valere') to remember that countervail means to offset or counterbalance.